1. Field of the Invention
The present invention relates to an expansion dowel including a cylindrical expansion body formed of at least two segments and having a through-bore with an inner shaped profile, and a recess formed in an outer profile of the expansion member with a radial depth of the recess diminishing in a setting direction of the expansion dowel; and an additional expansion element located in the recess and having a radial extent at least partially greater than a maximal depth of the recess.
2. Description of the Prior Art
Expansion dowels of the type described above have many applications and are used in particular as drive-in dowels for being set in constructional components formed, e.g., of concrete. When a drive-in dowel is to be set in a constructional component, first, a bore is formed in the constructional component into which the drive-in dowel is to be driven, and then the dowel is driven-in, e.g., with a percussion power tool. For expanding the dowel in the core, a bolt, which also serves as load application means, is inserted or is driven-in into the bore of the dowel in a setting direction. Preferably, the diameter of the bolt is substantially the same as the diameter of the through-bore of the expansion body of the dowel.
An expansion dowel of the type described above is disclosed in a German Utility Model DE-75 38457. The known expansion dowel has an expansion body formed of a plurality of segments hingedly connected with each other.
A drawback of the known expansion dowel consists in that the setting process is rather unwieldy because during the setting process the expansion body is not fixedly mounted on the load application means, e.g., on a bolt having a shaped outer profile.
Accordingly, an object of the present invention is to provide an expansion dowel having a segmented expansion body and which can be easily handled.
Another object of the present invention is to provide an expansion dowel having a segmented expansion body and capable of withstanding of high loads.
A further object of the present invention is to provide an expansion dowel having a segmented expansion body and which can be economically produced.
These and other objects of the present invention, which will become apparent hereinafter, are achieved by providing connection elements for connecting adjacent segments of the expansion body.
The connection of the adjacent segments, the expansion body is formed of, makes it possible to preassemble the dowel with load application means. If, e.g., an anchor rod is used as load application means, the connection elements, the separate segments are connected with, insure that the expansion dowel is mounted on the anchor rod without a possibility of an axial displacement therealong. The fixed mounting of the expansion dowel on the anchor rod frees the user from holding the dowel during the setting process. Further, the connection of the separate segments of the expansion body with the connection elements insures an exact positioning of the dowel on the anchor rod or the like during the setting process. Advantageously, all of the segments, which form the expansion body, are connected with each other by respective connection elements.
Advantageously, in order to provide for a reliable and economical connection of the expansion body-forming segments, the connection elements are formed so that they insure a snap connection of the segments with each other. In a preferred embodiment, the connection elements are so formed that they provide for a releasable snap connection of the segments. Naturally, instead of the snap connection, other forms of connection can be used such as, e.g., friction connection, chemical connection, etc.
Advantageously, the connection elements includes at least one hook-shaped element provided on at least one segment and a recess provided in another segment and in which the hook-shaped element engages, with formation of a form-locking connection between the connection elements. The use of the hook-shaped element and the recess insures, on one hand, economical formation of the connection elements and, on the other hand, obtaining a form-locking connection of the adjacent segments. A releasable connection is obtained by appropriate shaping of the hook-shaped element and the recess.
The segments are advantageously formed as semicircular shells, which permits to obtain a two-part expansion body that is easy to handle.
Preferably, the segments and the additional expansion element are formed of a plastic material.
When, e.g., the dowel needs to meet particular requirements, e.g., be fire-resistant, the segments and the additional expansion element are formed of metal.
According to a particularly advantageous embodiment of the present invention, the segments and the additional expansion element are formed of metal covered with plastics, using an injection-molding process. This insures easy manufacturing of the inventive dowel. Thereby it is insured that the connection elements, e.g., snap connection elements, can be easily provided on respective segments by the injection-molding process when the plastics is applied to the segments.
The novel features of the present invention, which are considered as characteristic for the invention, are set forth in the appended claims. The invention itself, however, both as to its construction and its mode of operation, together with additional advantages and objects thereof, will be best understood from the following detailed description of preferred embodiments, when read with reference to the accompanying drawings.